Antennas are used for a wide-variety of communications applications. One of the more recent applications for antennas has been for communications of point-to-point links for wireless fidelity “WiFi” communications. Various types of antennas may be used for point-to-point links for WiFi communications, but longer range communications, such as 20 miles, typically use dish-style antennas that have a radiation pattern that focuses an antenna beam more intensely along a communication path with another antenna. For example, while a flat panel antenna may have an antenna beam with a 60 degree angle, a dish antenna may have an antenna beam with a 6 degree angle, a much narrower beam than the flat panel antenna beam.
While the use of dish antennas for WiFi and other network communications is useful for providing long-distance communications between antennas, dish antennas that have such a small angle can result in problems if a misalignment occurs, especially at long distances. Misalignment of a dish antenna as small as one-half an inch can cause a dramatic loss of power at a range of 20 miles, for example, due to the antenna pattern not being focused on an antenna to which the dish antenna is in communication.
These antennas are often mounted on towers that situate the antennas between 50 feet and 400 feet above the ground. Dish antennas that may be used for such long distance communications are generally in the 18-inch to 6 foot diameter range and may weigh 100 to 150 pounds. The use of such large antennas may provide for communications qualities suitable for network communications, but may be problematic for maintaining alignment.
FIG. 1 is an illustration of a conventional point-to-point antenna communications system 100 illustrating the aforementioned misalignment of the antennas. FIG. 1 depicts two towers 102a and 102b with antennas 106a and 106b being coupled to the towers using mounts 104a and 104b. The mounts 104a and 104b typically include brackets and other hardware to lock the associated antenna in a fixed position on the respective towers. As a result of a slight misalignment, the signal 108 from antenna 106a is angled slightly downward, away from the receiving antenna 106b and, therefore, the antenna pattern 110 of the signal 108 is outside of the optimal receiving range of the receiving antenna 108.
Alignment problems may result from a number of reasons, including, and most often, weather conditions. Even though the brackets 104a and 104b are configured to lock the antennas 106a and 106b in a fixed position, weather conditions that produce a lot of wind, such as rainstorms and hurricanes, may cause the dish antennas being used for point-to-point network communications to become misaligned such that point-to-point communications degrade. While storms can be a problem, because an antenna may be located high above the ground, a ground wind speed of 20-30 miles per hour may be a wind speed of 80-100 miles per hour at the antenna. While these problems are generally associated with dish antennas being mounted on towers, the same or similar problems may exist from non-dish antennas or antennas positioned on other structures, such as buildings, poles, or the ground.
One problem that occurs due to the degradation of communications is that reliability of a network degrades to the point of an outage occurring. If an outage occurs for more than 6 minutes, a report to a governmental body, such as the Federal Communications Commission, must be made and, in some cases, fines may be imposed on a communications carrier that operates the network or maintains the communications link between the point-to-point antennas. Furthermore, the antenna manufacturer may have to lower reliability reporting of the antenna (e.g., from 0.999 to 0.99), which may cause communications carriers to lower their desire to purchase the antenna.
Another problem that results from misalignment of an antenna is that the cost for re-alignment pole or tower climbers (i.e., technicians who climb communications poles or towers) is expensive. For example, for a pole climber to climb a communications tower and re-align an antenna may cost $1,000 or more for a single climb. Furthermore, pole climbers are limited in supply and the time to have one perform the re-alignment may take hours or days. If a misalignment occurs during a storm with precipitation, pole climbers cannot climb the pole, so the misalignment may not be corrected until the storm passes, which may sometimes take several days. The costs due to misalignment may further be measured in customer attrition, which, if a misalignment occurs each time the wind blows strongly, can be significant.